Lyme borreliosis (or Lyme disease) has become a virtual household termto the exclusion of other forgotten, emerging or re-emerging borreliae.We review current knowledge regarding these other borreliae, exploringtheir ecology, epidemiology and pathological potential, for example, forthe newly described /B/. /mayonii/.

These bacteria range from tick-borne, relapsing fever-inducing strainsdetected in some soft ticks, such as /B/. /mvumii/, to those from batticks resembling /B/. /turicatae/. Some of these emerging pathogensremain unnamed, such as the borrelial strains found in South Africanpenguins and some African cattle ticks. Others, such as /B/. /microti/and unnamed Iranian strains, have not been recognised through a lack ofdiscriminatory diagnostic methods. Technical improvements inphylogenetic methods have allowed the differentiation of /B/./merionesi/ from other borrelial species that co-circulate in the sameregion.

Furthermore, we discuss members that challenge the existing dogma thatLyme disease-inducing strains are transmitted by hard ticks, whilst therelapsing fever-inducing spirochaetes are transmitted by soft ticks.Controversially, the genus has now been split with Lymedisease-associated members being transferred to /Borreliella/, whilstthe relapsing fever species retain the /Borrelia/ genus name. It tooksome 60 years for the correlation with clinical presentations now knownas Lyme borreliosis to be attributed to their spirochaetal cause.

Many of the borreliae discussed here are currently considered exoticcuriosities, whilst others, such as /B/. /miyamotoi/, are emerging assignificant causes of morbidity. To elucidate their role as potentialpathogenic agents, we first need to recognise their presence throughsuitable diagnostic approaches.